A wireless sensor network (WSN) (sometimes referred to as a wireless sensor and actuator network (WSAN)) are spatially distributed autonomous sensors or nodes to monitor/control physical or environmental conditions such as temperature, sound, pressure and so forth. Sensors or actuators on the network cooperatively pass collected data through the network to a central location where data is analyzed and stored and/or commands sent to operate the respective network nodes. Many networks are bi-directional, and thus also enable control of sensor activity. These networks and nodes are used in many industrial and consumer applications such as industrial process monitoring and control, machine health monitoring, and so forth. One important factor for operating nodes on the network is for very low power consumption.
Power consumption in such networks is an important factor as the devices employed at each node are relatively inexpensive and often times operate from battery power. One manner in which to reduce the power of low power wireless networks is to have intermittent data transfer (burst operation) when sending and receiving data to the nodes. Sleep timers are sometimes employed to synchronize the burst operations. Since the sleep timer is usually always ON, the sleep timer needs to be both very low power and very accurate for lowest system power. However, conventional crystal oscillator drivers in the sleep timers have large temperature variation and thus cause high power consumption at high temperature which reduces battery lifetime.